From mboxrd@z Thu Jan 1 00:00:00 1970 From: Steve Grubb Subject: Re: [PATCH ghak95] audit: Do not log full CWD path on empty relative paths Date: Fri, 24 Aug 2018 10:28:37 -0400 Message-ID: <1756482.jLK7dZV42z@x2> References: <20180802114436.1209-1-omosnace@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-audit-bounces@redhat.com Errors-To: linux-audit-bounces@redhat.com To: Ondrej Mosnacek Cc: Richard Guy Briggs , Linux-Audit Mailing List List-Id: linux-audit@redhat.com On Friday, August 24, 2018 8:59:10 AM EDT Ondrej Mosnacek wrote: > On Thu, Aug 2, 2018 at 1:45 PM Ondrej Mosnacek wrote: > > When a relative path has just a single component and we want to emit a > > nametype=PARENT record, the current implementation just reports the full > > CWD path (which is alrady available in the audit context). > > > > This is wrong for three reasons: > > 1. Wasting log space for redundant data (CWD path is already in the CWD > > > > record). > > > > 2. Inconsistency with other PATH records (if a relative PARENT directory > > > > path contains at least one component, only the verbatim relative path > > is logged). > > > > 3. In some syscalls (e.g. openat(2)) the relative path may not even be > > > > relative to the CWD, but to another directory specified as a file > > descriptor. In that case the logged path is simply plain wrong. > > > > This patch modifies this behavior to simply report "." in the > > aforementioned case, which is equivalent to an "empty" directory path > > and can be concatenated with the actual base directory path (CWD or > > dirfd from openat(2)-like syscall) once support for its logging is added > > later. In the meantime, defaulting to CWD as base directory on relative > > paths (as already done by the userspace tools) will be enough to achieve > > results equivalent to the current behavior. > > I tested this patch a little bit with the libauparse library (it has > some functions for normalizing paths extracted from the records) and > it seems to behave as intended. The userspace functions seem to take a > rather crude approach and I think they won't always properly normalize > some paths, but that is a separate issue and this patch at least > definitely doesn't make it worse. Be sure to test with directory names that have spaces in them as well as file names with spaces in them. -Steve > > See: https://github.com/linux-audit/audit-kernel/issues/95 > > > > Fixes: 9c937dcc7102 ("[PATCH] log more info for directory entry change > > events") Signed-off-by: Ondrej Mosnacek > > --- > > > > kernel/audit.c | 9 ++++----- > > 1 file changed, 4 insertions(+), 5 deletions(-) > > > > diff --git a/kernel/audit.c b/kernel/audit.c > > index 2a8058764aa6..4f18bd48eb4b 100644 > > --- a/kernel/audit.c > > +++ b/kernel/audit.c > > @@ -2127,28 +2127,27 @@ void audit_log_name(struct audit_context > > *context, struct audit_names *n,> > > audit_log_format(ab, "item=%d", record_num); > > > > + audit_log_format(ab, " name="); > > > > if (path) > > > > - audit_log_d_path(ab, " name=", path); > > + audit_log_d_path(ab, NULL, path); > > > > else if (n->name) { > > > > switch (n->name_len) { > > > > case AUDIT_NAME_FULL: > > /* log the full path */ > > > > - audit_log_format(ab, " name="); > > > > audit_log_untrustedstring(ab, n->name->name); > > break; > > > > case 0: > > /* name was specified as a relative path and the > > > > * directory component is the cwd */ > > > > - audit_log_d_path(ab, " name=", &context->pwd); > > + audit_log_untrustedstring(ab, "."); > > > > break; > > > > default: > > /* log the name's directory component */ > > > > - audit_log_format(ab, " name="); > > > > audit_log_n_untrustedstring(ab, n->name->name, > > > > n->name_len); > > > > } > > > > } else > > > > - audit_log_format(ab, " name=(null)"); > > + audit_log_format(ab, "(null)"); > > > > if (n->ino != AUDIT_INO_UNSET) > > > > audit_log_format(ab, " inode=%lu" > > > > -- > > 2.17.1 > > -- > Ondrej Mosnacek > Associate Software Engineer, Security Technologies > Red Hat, Inc.